Laparoscopic insufflation of the abdomen reduces portal venous flow

The adverse effects of sustained elevated intraperitoneal pressure (IPP) on cardiovascular, pulmonary and renal systems have been well documented by several reported experimental and clinical studies. Alteration in the splanchnic circulation has also been reported in animal experiments, but details of the exact hemodynamic changes in the flow to solid intraabdominal organs brought on by a raised intraperitoneal pressure in the human are not available. The aim of the present study was to estimate effect of increased IPP on the portal venous flow, using duplex Doppler ultrasonography in patients undergoing laparoscopic cholecystectomy.

The studies were performed using the SSD 2000 Multiview Ultrasound Scanner and the UST 5536 7.0-MHz laparoscopic transducer probe. Details of the measurements were standardized in according to preset protocol. Statistical evaluation of the data was conducted by the two-way analysis of variance (ANOVA).

The flow measurement data have demonstrated a significant (p < 0.001) decrease in the portal flow with increase in the intraperitoneal pressure. The mean portal flow fell from 990 +/- 100 ml/min to 568 +/- 81 ml/min (-37%) at an IPP of 7.0 mmHg and to 440 +/- 56 mmHg (-53%) when the IPP reached 14 mmHg.

The increased intraperitoneal pressure necessary to perform laparoscopic operations reduces substantially the portal venous flow. The extent of the volume flow reduction is related to the level of intraperitoneal pressure. This reduction of flow may depress the hepatic reticular endothelial function (possibly enhancing tumor cell spread). In contrast, the reduced portal flow may enhance cryoablative effect during laparoscopic cryosurgery for metastatic liver disease by diminishing the heat sink effect. These findings suggest the need for a selective policy, low pressure or gas-less techniques to positive-pressure interventions, during laparoscopic surgery in accordance with the disease and the therapeutic intent.